HQRP Wick Filter for Holmes HM1300, HM1600, HM1761, HM1700, HM1760, HM1760-UC, HM1740 Humidifiers + HQRP Coaster HQRP&reg; Humidifier Wicking Filter (Type A) Replacement + HQRP&reg; Coaster; Improves efficiency of the humidifier, traps mineral deposits from the water; Extended filter life with help of reinforced outer layer; Replace filter every 4-6 weeks, depending on usage and hardness of water; 2 weeks DOA replacement warranty!